1. Field of the Invention
The present invention relates to an attaching structure of a variable reluctance (VR) type resolver detecting a rotational position of a rotor, and a dynamo-electric machine provided with the attaching structure of the resolver, and an attaching method of the resolver.
2. Description of the Related Art
As shown in FIG. 7, a conventional DC brushless motor 100 is provided with a resolver rotor portion 104 attached to a shaft 102, a resolver stator portion 106 arranged in an outer side in a diametrical direction of the resolver rotor portion 104, and a coil portion 108 positioned in both sides in an axial direction of the resolver stator portion 106. A rotational position of the shaft 102 is detected by the resolver rotor portion 104 and the resolver stator portion 106.
In this case, the resolver stator portion 106 and the coil portion 108 are received in a case member 110. The case member 110 is arranged in a concave portion 116 of a resolver stator portion side attaching portion 114 formed in a housing 112. A positioning groove 118 having a bottom surface portion 118A and a vertical surface portion 118B is formed in an inner peripheral surface of the concave portion 116. In a state in which the case member 110 is arranged in the concave portion 116, an outer side surface 106C in a diametrical direction of the resolver stator portion 106 is brought into contact with the bottom surface portion 118A, and a side surface 106B in one side in an axial direction of the resolver stator portion 106 is brought into contact with the vertical surface portion 118B. Further, a cover member 120 is attached to the resolver stator portion side attaching portion 114 by a bolt 122. In a state in which the cover member 120 is attached to the resolver stator portion side attaching portion 114, the cover member 120 is brought into contact with the side surface 106C in the other side in the axial direction of the resolver stator portion 106.
As the attaching structure of the resolver, there are structures disclosed in Japanese Patent Application Laid-open No. 2002-136055 (patent document 1) and Japanese Utility Model No. 2543173 (patent document 2).
In the structure in which the outer side surface in the diametrical direction of the resolver stator portion is brought into contact with the bottom surface portion, and the side surface in one side of the resolver stator portion is brought into contact with the vertical surface portion, an accuracy of assembling position is lowered with respect to the resolver rotor portion of the resolver stator portion in the case that a dimensional error of the concave portion is generated. Accordingly, there is a problem that a rotational position of the shaft cannot be accurately detected. In particular, in the case that both side end surfaces of the resolver stator portion are pinched by the vertical surface portion of the concave portion of the resolver stator portion side attaching portion and the cover member so as to be positioned and firmly fixed, a magnetic strain caused by a great fastening force is generated in the resolver stator core by a fastening member of the cover member, so that there is a problem that an accuracy of detection is diminished.